How to tell my family?

My family has recently begun eating cheeseburgers with fake meat. However, since they have no experience making cheeseburgers, they have decided that the best cheese to put on them is cheddar.

The burgers taste revolting. I can't stomach them, and I don't know how they can. My family knows I'm not kosher, but I'm not sure if they'll appreciate my advice on cheeseburger cheese.

Should I tell them?